Blogs

Are
you familiar with the story of Exodus? About 4000 years ago, Moses led the
Hebrew people out of Egypt. They
were however, closely pursued by Pharaoh’s chariots. The story states that some
relative motion of water and land delayed or destroyed the Egyptian forces and
allowed the Hebrews to escape.

We’ve
all seen the Hollywood telling of this event in the “Ten Commandments”, where
Charlton Heston splits the Red Sea for a while, then zips it back up over the
tailing troops.

A moderate earthquake originally estimated as having a magnitude M=5.0, but later downgraded to 4.8 and then 4.4, has struck NE of Ottawa, Canada. It was felt over a wide range of eastern Canada and the northeastern part of the United States. By our calculations, it struck in a region of low probability.

As discussed in previous posts, incomplete or unavailable data can seriously impact the quality of earthquake forecasts. In our case, these problems are associated with the Global Digital Seismic Network, funded and maintained by the US National Science Foundation, and the US Geological Survey, among others. The data catalogs also contain contributions from local networks in various countries.

This week the UN ESCAP group is holding a series of meetings in Bangkok aimed at disaster resilience and reduction of natural diasters for Asia and the Pacific. A report and a website document the problems. The report is particularly interesting in that it links natural disasters with financial disasters such as the current global crisis and suggests common approaches.

On monday April 16, a M7.8 earthquake struck near the borders of Iran, Pakistan and India. Continuing on the theme of the last blog, the lack of small earthquake data in some regions of the globe is again illustrated. The first figure below is a screen shot of the affected region. Again, the radius of the circle is 243 km = 150 miles.

In the last day we have seen two earthquakes having magnitudes M>6. The first was a M6.6 event near Ya'an, China, which, according to news accounts, killed more than 150 persons, and injured more than 5500. The second earthquake was a M6.1 event that occurred in the Kamchatka region following a M6.9 earthquake on February 28.

Sorry about the long absence. Been working on the new Open Hazards social networking site (more about that in a later post). Time to revisit the changes in spatial contours at various locations in the world, starting with southern California. I'll be presenting some of this at the Seismological Society of America meeting next week in Salt Lake City.

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About OpenHazards Bloggers

Steven Ward is a Research Geophysicist at
the Institute of Geophysics and Planetary Physics, UC Santa Cruz. He specializes in the quantification and simulation of
natural hazards. Read Steve's blog.

John Rundle is a Distinguished Professor of Physics
and Geology at UC Davis and
the Executive Director of the APEC Collaboration for Earthquake Simulations. He
chaired the Board of Advisors for the Southern California Earthquake Center from 1994 to 1996. Read John's blog.